Question 1

Which of the following best explains why DNA is considered the genetic material in cells?

Accepted Answer

DNA's sequence of nitrogenous bases encodes genetic information, and its complementary double-helix structure allows for accurate replication.

Question 2

Which of the following statements correctly distinguishes prokaryotic and eukaryotic chromosomes?

Accepted Answer

Prokaryotic chromosomes are single, circular, and found in the nucleoid, while eukaryotic chromosomes are multiple, linear, and packaged with histone proteins in a nucleus.

Question 3

During bacterial DNA replication, which enzyme is responsible for joining Okazaki fragments on the lagging strand?

Accepted Answer

DNA ligase

Question 4

A mutation causes the insertion of two nucleotides into a gene. What type of mutation is this, and what is its likely effect?

Accepted Answer

Frameshift mutation; likely to produce a nonfunctional protein due to altered reading frame.

Question 5

Which of the following best describes the function of a bacterial operon?

Accepted Answer

A cluster of genes under the control of a single promoter, allowing coordinated expression of related proteins.

Question 6

In the process of transcription in bacteria, what is the role of the promoter?

Accepted Answer

It is the site where RNA polymerase binds to initiate transcription.

Question 7

Which of the following is a correct sequence of events during translation in bacteria?

Accepted Answer

Ribosome binds to mRNA, tRNA brings amino acids, peptide bonds form, ribosome reaches stop codon, protein is released.

Question 8

Which DNA repair mechanism is specifically activated in response to extensive DNA damage and can introduce mutations as a trade-off for survival?

Accepted Answer

SOS response

Question 9

A scientist wants to introduce foreign DNA into bacterial cells by creating temporary pores in their membranes using an electric field. Which technique is being used?

Accepted Answer

Electroporation

Question 10

Which of the following best describes the action of restriction enzymes in genetic engineering?

Accepted Answer

They cut DNA at specific recognition sites, enabling the creation of recombinant DNA.

Question 11

A bacterial cell acquires new genetic traits by absorbing DNA fragments from its environment. What is this process called?

Accepted Answer

Transformation

Question 12

Which of the following is a potential ethical concern associated with genetically modified organisms (GMOs) in agriculture?

Accepted Answer

Herbicide-resistant GMO plants may crossbreed with nuisance weeds, making them harder to control.

Question 13

Which of the following is NOT a step in bacterial DNA replication?

Accepted Answer

Transcription of mRNA from the lagging strand.

Question 14

A point mutation changes a codon from $$\mathrm{GAA} to$$ $$\mathrm{GAG}$$, both of which code for glutamic acid. What type of mutation is this?

Accepted Answer

Silent mutation

Question 15

Which of the following best describes the difference between inducible and repressible operons?

Accepted Answer

Inducible operons are normally off and can be turned on by an inducer, while repressible operons are normally on and can be turned off by a corepressor.

Question 16

Which of the following is an example of vertical gene transfer in bacteria?

Accepted Answer

A parent cell replicating its genome and supplying copies to its descendants during cell division.

Question 17

A researcher uses calcium chloride and a brief heat shock at $$42^\circ\mathrm{C} to $$introduce plasmid DNA into E. coli. What is the main purpose of the heat shock step?

Accepted Answer

To increase membrane permeability, allowing DNA to enter the cell.

Question 18

Which of the following is a real-world application of recombinant DNA technology in the medical field?

Accepted Answer

Producing safer and more effective vaccines quickly and inexpensively.

Question 19

A virus accidentally packages bacterial DNA and transfers it to another bacterium. What is this process called?

Accepted Answer

Transduction

Question 20

Which of the following best describes the role of biotechnology in environmental cleanup?

Accepted Answer

Using microbes and enzymes to break down organic waste and clean up contaminated environments.

Fundamentals of Microbial Genetics and Biotechnology

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